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Volume 25 (1960)
- Issue 5 Pages 205-
- Issue 4 Pages 167-
- Issue 3 Pages 125-
- Issue 2 Pages 71-
- Issue 1 Pages 1-
Volume 25, Issue 2
Displaying 1-7 of 7 articles from this issue
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Hazime YOSHII1960 Volume 25 Issue 2 Pages 71-74
Published: July 25, 1960
Released on J-STAGE: February 19, 2009
JOURNAL FREE ACCESSDownload PDF (515K) -
Tadao MISAWA, Sakari KATO1960 Volume 25 Issue 2 Pages 75-79
Published: July 25, 1960
Released on J-STAGE: February 19, 2009
JOURNAL FREE ACCESSWhen the rice stem rot fungus (Leptosphaeria salvinii Cattaneo) is cultured for a long time, most of the isolates lose their ability to produce sclerotia. Such sterile isolates, however, regained their ability, when the decoctions of leaves, leaf-sheaths and stems of rice plant were added to culture media. It is suggested that some substances involved in rice plant may play a difinite rôle in this recovery of ability for sclerotia production.
The bioactive substances were not extracted by distilled water, alcohol, acetone, ether, HCl, H2SO4, or NaOH. Because of insolubility in these solvents, it was inferred that nucleic acid may be one of the suspected substances. When RNA was added to the synthetic liquid media at a rate of 4∼8mg per litre, the isolates which had ceased to produce sclerotia, came to form sclerotia. On the synthetic media added with DNA at a rate of 4mg per litre, however, sclerotia production was not incited.
In the cells of mycelia and pseudoparenchyma of sclerotia, developed on RNA-added synthetic media, oil drops were found more abundantly than in those grown on RNA-absent media. Lipase activity of mycelia was found to be increased by addition of RNA to the medium. Such increase of the fatty substances in the vegetative mycelium may represent a preparative stage for the formation of sclerotia.
The paper-electrophoresis patterns obtained with the extracts from mycelia grown on RNA-added media, indicated that there are three protein components, being similar to those obtained with the extract from sclerotia. The extracts from mycelia grown on RNA-absent media showed four protein components.
From the results given above, it seems that disturbances in RNA metabolism may be one of the causes for the loss of sclerotia producing ability of the fungus cultured on artificial media.View full abstractDownload PDF (683K) -
II. On the activities of β-amylase and invertase in tissues surrounding spotsHiroyasu TANAKA, Shigeyasu AKAI1960 Volume 25 Issue 2 Pages 80-84
Published: July 25, 1960
Released on J-STAGE: February 19, 2009
JOURNAL FREE ACCESS1. In the present paper, the writers described the result of investigations on the contents of starch and sugars, and also the activities of β-amylase and invertase in the different parts of diseased leaves of rice plant infected by Cochliobolus miyabeanus.
2. In the tissue surrounding the spotted area, the content of starch increased and the activity of invertase was promoted, but the decrease was found in both the content of sugars and the activity of β-amylase. On the other hand, in the healthy part of diseased leaves, only the decrease in sugar content was recognized.
3. Judging from these experimental results, it may be conceivable that the mechanism of this abnormal starch acculation is partially based on the decreased activity of β-amylase in the area surrounding the spots.View full abstractDownload PDF (627K) -
II. Effect of durations of mounting the spore suspension on the pea pod, and pre-infection treatment of pea pod with ether or heat, upon phytoalexin productionKazuo UEHARA1960 Volume 25 Issue 2 Pages 85-91
Published: July 25, 1960
Released on J-STAGE: February 19, 2009
JOURNAL FREE ACCESSExperiments were carried out to study the effect of the length of time of incubation with spore suspension of Ascochyta pisi Libert, and of preinfectional treatments of pea pod with ether gas or hot water, on production of an antibiotic factor, phytoalexin, by pea pod. The methods in general are described in the previous paper. Germination test of Ascochyta spore for bioassay of phytoalexin, was modified to use agar blocks (5×5×1-0.5mm) suspended with conidia, in place of spore suspension.
The antibiotic activity of diffusate could not be detected in the spore suspension mounted on the seed cavities of pea pod for 8 hours, but was recognized in the plot incubated for 12 hours, and increased with the length of incubation time. It reached the maximum when spore suspension was incubated for 20∼30 hours (Tables 1 and 2, Fig. 1).
The activity of pea pod to produce the antibiotic factor was destroyed by either anesthetic treatment with ether (at a rate of 1.1cc ether in 4.71 volume of air, for 24 hours at 17∼22°C), or heat treatment at 40°C for 60∼90 minutes, before inoculation with spore suspension (Tables 3 and 4).View full abstractDownload PDF (886K) -
VI. Breakdown of disease resistance of rice plant by treatment with reducing agentsHachiro OKU1960 Volume 25 Issue 2 Pages 92-98_1
Published: July 25, 1960
Released on J-STAGE: April 03, 2009
JOURNAL FREE ACCESSThe resistance of the leaf-sheath cells of rice plants against Cochliobolus miyabeanus was markedly decreased by adding reducing agents, such as ascorbate or glutathione, to the inoculum.
Phytoalexin-like antifungal substance was produced as a result of interaction between the cells of rice plants and the germinating spores of C. miyabeanus. However, since ascorbate and glutathione did not either decrease the activity of phytoalexin, or did not inhibit the formation of such a substance, the active principle in resistance which was inactivated by adding reducing agents would not be referred to the activity of phytoalexin.
The invaded cells of leaf-sheath and their neighbouring cells were oxidatively stained with various rH indicators at the begining of hyphal penetration. It is noticeable that the parts of mycelia which were in contact with the membranes of inner epidermal cells of the leaf-sheath were also oxidatively stained in deep colour. The invaded cells of the resistant variety, Kameji, were stained with methylene blue in green colour at the begining of invasion, while in the susceptible variety, Asahi, the colour reaction was nearly blue.
Judging from these results, it was concluded that the resistance of rice plant against hyphal penetration of C. miyabeanus is, to some extent, attributable to the fungal oxidation products, perhaps quinones, which are derived from the host cells or membranes.View full abstractDownload PDF (1848K) -
H. YASUMORI1960 Volume 25 Issue 2 Pages 103-104
Published: July 25, 1960
Released on J-STAGE: February 19, 2009
JOURNAL FREE ACCESSDownload PDF (239K) -
1960 Volume 25 Issue 2 Pages 106-120
Published: July 25, 1960
Released on J-STAGE: February 19, 2009
JOURNAL FREE ACCESSDownload PDF (2254K)
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